# Author    :Dun_Hz
# Time      :2024/7/26 11:40

def linear_search(li, val):
    for index, v in enumerate(li):
        if v==val:
            return index
    return None

if __name__=="__main__":
    li=[1,56,7,9,435,643,45,52]
    val=9
    print(linear_search(li,val))